The synthesis and turnover of lipids in cultured animal cells, transformed or productively infected with Rous sarcoma virus or herpes virus, will be ascertained using short pulse-chase studies. A comparative study of enzymes responsible for phospholipid renewal will be done using subcellular membrane fractions. CDP-intermediates will be synthesized chemically and used tostudy the effect of viral infection and/or transformation using cell-free systems. The synthesis and transport of phospholipids to sites of viral envelope biogenesis and/or transformation will be studied by electron autoradiography.